Shallow Ditch Safety in Anisotropic Clay

Abstract

The potential collapse of temporary unsupported shallow vertical cuts in soil poses an extremely hazardous condition during the construction process. The conventional method of analyzing the safety of slopes is done by assuming the failure surface to be the arc of a circle. More recently, Ellis presented a stability analysis of shallow ditch cuts in homogeneous soil assuming the failure surface to be a cycloidal arc. In the preceding analysis, the tensile strength of soil and the shear stresses on the vertical planes due to horizontal compressive stresses of the trial section were neglected. The factor of safety of the cut was defined as the minimum value of the ratio of the available shear strength to the mobilized shear strength along any point of the critical failure surface. Essentially, the purpose of this paper is to extend the stability analysis of temporary shallow vertical cuts conducted by Ellis to anisotropic clay and to determine the effect of clay anisotropy on the factor of safety of the cut. In this study, the assumptions used will be similar to those of Ellis, and the failure surface will be taken as a cycloidal arc.